.video-js .vjs-big-play-button{
    width: 50px;
    height: 50px;
    border-radius: 30px;
    position: absolute;
    top: 50%;
    left: 50%;
    margin: -25px 0px 0px -25px
}
.vjs-poster{
    background-size: 100% 100% ;
}